X Factor star Anthony Russell has paid an emotional tribute to Louis Tomlinson‘s late sister Félicité, following the 18-year-old’s heartbreaking death this week.

The singer, 28, who was mentored by One Direction star Louis during the ITV series in 2018, took to Instagram to share a heartfelt message to the teen following her suspected heart attack.

Anthony shared a photo of himself with Félicité, with the duo seen beaming away to the camera, while in another snap, Anthony could be seen standing in between Louis and Félicité.

Tribute: X Factor star Anthony Russell, 28, has paid an emotional tribute to Louis Tomlinson’s late sister Félicité, following the 18-year-old’s heartbreaking death this week

Captioning the heartwarming images, he wrote: ‘I don’t know what to say, I can’t put it into words the sadness I feel or the heartbreak I feel for this amazing family.

‘I am sending all my love and strength to u all and I love u all so much. Félicité I love you always.’

His emotional message was greeted with several comments of support from his fans.

Louis has been left ‘devastated and ­distraught’ by the death, The Sun reported, and praised his sister as ‘loveable, caring, bright and beautiful’, sources close to the One Direction singer told the paper.

Tragic: The singer, who was mentored by One Direction star Louis during the ITV series in 2018, took to Instagram to share a heartfelt message to the teen

Tragic: Félicité collapsed after a suspected heart attack at her fourth-floor studio apartment in Earls Court, West London, on Wednesday lunchtime

He pulled out of Friday night’s Comic Relief, where he was due to perform his new single live as one of the headline acts.

Félicité collapsed after a suspected heart attack at her fourth-floor studio apartment in Earls Court, West London, on Wednesday lunchtime.

It is understood police found no signs of drugs at the address.

Painful: Louis pulled out of Friday night’s Comic Relief, where he was due to perform his new single live as one of the headline acts

Pals: Anthony and Louis formed a close bond during his first stint on the X Factor, after he dropped out of the competition to seek treatment for drug addiction (pictured in 2018)

Anthony and Louis formed a close bond during his first stint on the X Factor, after he dropped out of the competition to seek treatment for drug addiction.

The Just Hold On singer reached out to the aspiring singer, lending him support and even offering to pay for treatment.

Anthony has in the past said that he ‘would be dead’ if Louis hadn’t ‘saved him’.

Sweet: The Just Hold On singer reached out to the aspiring singer, lending him support and even offering to pay for treatment (pictured hugging in 2018)